Last night, sick of not listening to music in my new car, I replaced the factory deck with an analog audio input. I used a
connector from eBay ($4) and some bits I had laying around.
My car had a phone in its former life, so the coin tray has a big hole in the bottom of it. I decided that entitled me to proceed with reckless abandon, so I drilled holes for the audio and Lightning connector at the back of the coin tray and hot-melt glued the cables in place:
This hideous mess, from the topside, looks like this:
And with my phone plugged in, looks like this:
I paired the front and rear inputs to the factory harness; from testing the left and right each appear to provide signal to the sub and rear speaker. The red (switched-power) wire on the harness connector mates to the blue (antenna) wire; that turns on the amps when the ignition is on. I unplugged the antenna in the trunk so it stays down. The Lightning connector runs into the ash tray, where it may be plugged into a USB-power adapter. I would have wired this directly and tucked it away but the lighter-plug-to-USB converters I have are ultra cheap and seem to have a tendency to get hot. I prefer not to convert my NSX to a smoldering pile of toxic waste due to a $0.30 piece of junk. Ultimately I will likely replace this with a reputable 12V-5V converter hardwired.
The signal level from my iPhone 5 headphone output is nearly perfectly matched to the Bose amps. A good volume is around 60-80% on the phone.
It's nice to be able to plug the phone in where I tended to set it anyway and both charge it and listen to music. The hardware volume buttons are just accessible on the side of the phone. Nav on the iPhone will play through the system. My only problem is phone calls, which will play audio through the system but expect me to speak into the microphone on the phone. I use a bluetooth headset so I don't think this will be an issue but we'll see. It's possible that I may want a bluetooth handsfree kit with a switch to select between that and a direct audio connection.
This setup is only appropriate for my phone (or other naked iPhone 5's), but that's okay with me and a new coin tray could be made for a new phone. I would prefer a better location for the phone but I'm going to live with this for a bit and see how it goes.
-jason